Stabilizing agent for single powder photographic developers



Patented Aug. 5, 1952 ATENT oFFicE STABILIZING AGENT FOR SINGLE POWDER PHOTOGRAPHIC DEVELOPERS William J. Rogers, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application February 9, 1951, Serial No. 210,284

11 Claims. (01. 95-38) 1 relates to This invention single-powder photographic developers, and more particularly to a single-powder developer in which the ingredients of the developer are intimately mixed in the form of dry powder with powdered boric anhydride, which contains free moisture not in excess of 15.0% by weight, as a stabilizing agent to prevent disadvantageous interaction between the organic developer component-and the basic component of the single-powder mixture.

Single-powder developer mixtures may contain an organic developer component or mixtures of such components, including monomethylparaminophenol sulfate (elon or metol), hydroquinone, p-aminophenol hydrochloride, p-aminophenol sulfate, pyrogallol, parahydroxyphenyl glycine, catechol, diaminophenol hydrochloride, and others, with an alkali component, a stabilizing component, an oxidizing preventer and an anti-fogging component. The alkali component may be the stable hydrate of an alkali carbonate, a desiccated alkali carbonate, an alkali metaborate, or an alkali sulfite. Generally the stable alkali carbonate monohydrate is preferred. The oxidation preventing component may be an alkali sulfite, and the anti-fogging component may be potassium bromide or iodide. Stabilizing components for such a single-powder developer are disclosed in Patent 2,384,592 of September 11, 1945 and include maleic anhydride, salicylic acid, alkali metabisulfite, benzoic anhydride, orthobenzoic sulfimide, phthalimide, and phthalic anhydride. The latter has outstanding stabilizing properties in the presence of either sodium carbonate or borax and has been employed considerably more than the other stabilizers mentioned in the patent.

While the stabilizing effect of the phthalic anhydride is verygood, it has been employed most successfully in developer compositions having as the alkali component either sodium carbonate or sodium sulfite, or mixtures thereof. Less success has been attained in the case ofthe important class of developers containing sodium metaborate as the alkali ingredient. Also, the presence of phthalic anhydride in the singlepowder developer involves other considerations which are not too desirable. In the first place, phthalic anhydride is slowly soluble in water. Furthermore, it is impossible to employ it in the presence of benzotriazole, the latter being a desirable component of certain developer mixtures. But the greatest disadvantage of employing phthalic anhydride in single-powder developer mixtures, which contain alkali carbonates and sulfite, is that phthalic anhydride may react due in part to temperature effects with these basic substances and form gas under sufficient pressure to distend the hermetically sealed can in which the developer powder is packaged, and often cause a portion of the powder to be ejected with some violence as the package is opened.

An. object, therefore, of the presentinvention is to provide an improved stabilizing agent for single-powder developers.

Another object of the invention is to provide an improved stabilizing agent for single-powder developers which does not possess the disadvantages caused by employing phthalic anhydride as the stabilizing agent.

A further object of the invention is to provide an improved stabilizing agent which makes possible the production of single-powder developers having improved stabilizing characteristics containing as the alkali ingredient, sodium metaborate.

In accordance with the invention these and other objects are attained by employing boric anhydride as the stabilizer instead of other previously known stabilizers in such single-powder developers which contain both organic developer components and basic components. The boric anhydride employed in accordance with my invention may contain free moisture up to 15.0% by weight and when the term boric anhydride is mentioned in this specification I mean boric anhydride with a moisture content within this range.

I have found that such bori'c anhydride eliminates the objectionable characteristics possessed by phthalic anhydride. It appears that boric anhydride being much less acid than phthalic anhydride does not react as easily or as violently as phthalic anhydride with alkali carbonates or alkali sulfites such as NazCOa and NazSOx. In this respect it is noted that the pH of phthalic anhydride is about 2.4 while the pH of boric anhydride is about 5.4 at 3 concentrations. Borio anhydride is admirably suited as a stabilizer and has the characteristics required for a stabilizer. It is acidic, relatively colorless, odorless, and stable and has no deleterious action photographically.

A preferred embodiment of the present invention involves the use in the single-powder photographic developer mixture of either the stable hydrate of an alkali carbonate or also a desiccated alkali carbonate. The alkali carbonate hydrate appears to be more stable in the presence .lmage.

diaminophenol hydrochloride, and suitable mix-- tures thereof, a stable alkali carbonate, such as sodium carbonate monohydrate; and boric anhydride, and may contain the other well known ingredients normally present in a developer, such .as sodium sulfite and potassium bromide, the

normal and known function of the alkali 'sulfite being that of preservative, lessening the oxida- :tion in solution of the organic developing agent; while the known function of potassium bromide is that of a restrainer particularly inhibiting "fog" formation in the development of thesilver These known components and their ;known functions in a photographic developer are :not to be considered as forming part of this 'in- .vention, nor is their mention herein to be construed as limiting thevscope of the proposed single-powder developer mixtures. 4

In compounding the developer mixture, one :may proceed by first mixing the stabilizer and the basic component, adding and mixing therewith the developing agent, which is followed by incorporating the other ingredients. 'However, \one can mix all the ingredients together at the :same time. I I I I The following examples will 'servelfurther to illustrate developer mixtures within the scope of the invention and will also indicate. the proportionate quantities in which the respective components can be mixed together in a dry form to makeup such single powder photographic developer mixtures.

Example 1 Grams Elon (monomethylp-aminophenol sulfate) 3.1 :Anhydrous sodium sulfite 45.0 .Hydroquinone 12.0 Sodium carbonate monohydrate 81.3 Potassium bromide 1.9 Borlc anhydride 4.2

'Exa'mplez I Grams ,Elon 1 .5 ,Anhydrous sodium sulfite "2 25 'Hydroquinone "6.3 ,Sodium carbonate, desiccated .1... 15.0 ,Potass'ium bromide 1.5 ;Boric"anh'yclride 1.0

Example 3 'Elon Anhydrous sodium sulfite Hydroquinone 8.8 Sodium carbonate monohydrate 57.5 Potassium'bromide 5.0 .Boric anhydride 3.4

Example 4 I Grams -Elon 2.5 Anhydroussodium sulfite 30.0 .Hydroquinone {2.5 Sodium metaborate 10.5 ,PQtassium brom d I05 Bone "anhydride ;l.; '41? Example 5 r I Grams Sodium sulfite 50 Sodium carbonate monohydrate 54 Potassium bromide 1 B'oric anhydride QQ 2.2 Pyroga1lol' 6.3

Example 6 I I I II Grams Sodiumsulfite 50 Sodium carbonate monohydrate 54 ,Potassium bromide 1 ,Boric. anhydride 2.2 Catechol 5.5

Example 7 Grams Sodiumsulfite 50 Sodium carbonate monohydrate 54 Potassium bromide 1 Boric anhydride 2.2 p-Hydroxyphenyl glycine 8.4

Example 8 I I I Grams Sodium sulfite 50 Sodium carbonate monohydrate Q 54 Potassium bromide l. Boric anhydride 2.2 p-Aminophenol sulfate Q 7.3

' Example 9 I Grams Sodium sulfite L; f 50 Sodium carbonate monohydrat 54 Potassium bromide 1- Boric'anhydride .2 p-Aminophenol hydrochloride 7.3

Example 10 I II II Grams Sodium sulfite 'I I IL 75 Sodium carbonate monohydrate 30 Potassiumiodide .01 ,Bo'ric anhydride 2.2 ,Hy'droquinone 9 Elon' 1 Example 11 r II I II I Grams Elon 10.0 Anhydrous sodium sulfite 100.0 .Sodiumxnetaborate 20.0 Boric anhydride 4.0 Example 12 w Elon "5; Sodium sulfite, desiccated "100.0 Boric anhydride 1.1

Example 13 I Grams Sodium sulfite. 96

Sodium carbonate monohydrate Potassiumbromide k water to make one liter of solution.

Samples of the mixtures as given in the examples have been found, even after the mixtures have been kept in hermetically sealed cans at 120 F. for prolonged periods, to be unimpaired in developing properties and to give a solution comparable in color to solutions prepared from such chemicals not previously mixed. No expansion of the package in which the compositions were stored was noted as contrasted to the devel: opers similar in composition except that phthalic anhydricle replaces the boric anhydride of the present invention. The term developing agent in the claims is to be interpreted as comprising .either one or several separate organic developer compounds.

What I claim and desire to secure by Letters Patent of the United States is:

1. A stable single-powder photographic developer composition containing an organic silver halide developer, a stabilizing agent, comprising boric anhydride having free moisture content not exceeding approximately 15.0% by weight and a soluble, stable, and photographically compatible basic ingredient selected from the group consisting of alkali borates, sulfites and carbonates.

2. A stable single-powder photographic developer composition containing an organic silver halide developer, sodium carbonate monohydrate, and boric anhydride containing less than 15.0% free moisture.

3. A stable single-powder photographic developer containing an organic silver halide developer, alkali carbonate, an alkali sulfite and boric anhydride containing less than 15.0% by weight of free moisture.

4. A stable single-powder photographic developer containing an organic silver halide developer, an anhydrous alkali carbonate, an alkali sulfite and boric anhydride containing less than 15.0 by weight of free moisture.

5. A stable single-powder photographic developer composition, containing an organic silver halide developer, desiccated sodium sulfite and boric anhydride containing less than 15.0% by weight of free moisture.

6. A stable single-powder photographic developer composition containing an organic silver by weight of free moisture and 8.4 grams p-hydroxyphenyl glycine.

8. .A stable single-powder photographic developer composition consisting of approximately 50 grains sodium sulfite, 54 grams sodium carbonate monohydrate, 1 gram potassium bromide, 1.1 grams boric anhydride containing less than 15.0% by weight of free moisture and 7.3 grams paminophenol sulfate.

9. A stable single-powder photographic developer composition consisting of approximately 50 grams sodium sulfite, 54 grams sodium carbonate monohydrate, 1 gram potassium bromide, 1.1 grams boric anhydride containing less than 15.0% by weight of free moisture and 7.3 grams paminophenol hydrochloride.

10. A stable single-powder photographic developer composition consisting of approximately 3.1 grams monomethyl p-aminosulfate, 12 grams hydroquinone, grams anhydrous sodium sulfite, 81 grams sodium carbonate monohydrate, 1.9 grams potassium bromide, and 4.2 grams boric anhydride containing less than 15.0% by weight of free moisture.

11. A stable single-powder photographic developer composition consisting of approximately 59 grams sodium sulfite, 3.2 grams potassium bromide, 34.6 grams diaminophenol hydrochloride and 2.9 grams boric anhydride containing less than 15.0% by Weight of free moisture.

WILLIAM J. ROGERS.

REFERENCES CITED UNITED STATES PATENTS Name Date Bean Sept. 11, 1945 Number 

1. A STABLE SINGLE-POWDER PHOTOGRAPHIC DEVELOPER COMPOSITION CONTAINING AN ORGANIC SILVER HALIDE DEVELOPER, A STABILIZING AGENT, COMPRISING BORIC ANHYDRIDE HAVING A FREE MOISTURE CONTENT NOT EXCEEDING APPROXIMATELY 15.0% BY WEIGHT AND A SOLUBLE, STABLE AND PHOTOGRAPHICALLY COMPATIBLE BASIC INGREDIENT SELECTED FROM THE GROUP CONSISTING OF ALKALI BORATES, SULFITES AND CARBONATES. 